Oreostemma peirsonii
Peirson's aster
(c) Trevor Van Loon, some rights reserved (CC BY), uploaded by Trevor Van Loon · licence
Family: Asteraceae · Type: Herb · Native
Oreostemma peirsonii (Peirson's aster) is a native California herb in the Asteraceae family, recognized by diminutive size and glandular texture.
Peirson's aster is a California native perennial found in southern Sierra Nevada Mountains on rocky slopes, ridges, and dry meadows at elevations of 3,000 to 3,800 meters. Flowering from July to September, this plant produces white ray flowers 12 to 16 millimeters long with distinctive glandular stems and leaves. Growing with compact stems just 2 to 7 centimeters tall, it forms dense, low-growing clusters in alpine environments. Its leaves are narrow and linear, densely covered with short glandular hairs that give the plant a distinctive sticky texture. The flower heads feature leaf-like phyllaries with tan edges and soft, slightly hardened bracts.
Identification and appearance
Key characters: Co-occurs with 2 species; diminutive size and glandular texture are diagnostic
Habitat and range
Habitat: Rocky slopes, ridges, dry meadows
Elevation: 3000-3800 m
Bloom period
Oreostemma peirsonii blooms Jul-Sep.
How to tell it apart
vs Erigeron: Oreostemma has mostly basal leaves on nearly leafless stems; Erigeron typically has leaves along stem.; vs Symphyotrichum: Oreostemma has solitary heads and basal leaves; Symphyotrichum has clustered heads and stem leaves.; vs Aster: Oreostemma has solitary heads with basal leaves; Aster typically branched with stem leaves.; vs Syntrichopappus: Oreostemma smooth to slightly hairy; Syntrichopappus densely woolly overall.
Frequently asked questions
Is Oreostemma peirsonii native to California?
Yes. Oreostemma peirsonii is native to California (recorded as native).
When does Oreostemma peirsonii bloom?
Oreostemma peirsonii blooms Jul-Sep.
What plant family does Oreostemma peirsonii belong to?
Oreostemma peirsonii is in the Asteraceae family, genus Oreostemma.
What habitat does Oreostemma peirsonii grow in?
Oreostemma peirsonii grows in Rocky slopes, ridges, dry meadows.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.